graeme_p - 7:29 pm on Sep 25, 2011 (gmt 0)

It is interesting to consider whether a machine trying to judge the quality of a page would conclude that an article with long sentences, excessive punctuation and lots of long words (presumably the main factors that constitute 'advanced reading level') would in all probability also be a poor quality article, for example because spam, spun and auto-translated page share the same attributes.

You could also conclude that grammatically correct complex sentences, and a consistently complex style are likely to be the work of a competent human author.

I would concentrate on writing well for your audience, which will influence the number of incoming links, which we know is a key factor, rather than guessing what Google wants.